Motivation
While disabling Evil in holy-mode makes its implementation shorter and
sounds elegant on the paper, in practice it puts a big burden on the
configuration parts which need to know if Evil is enable or not. This is
a bad separation of concerns and the bunch of fixes that we were forced
to do in the past weeks shows this issue. Those fixes were about
removing the knowledge of the activation of Evil by implementing new
dispatching functions to be used by layers, this is cumbersome and makes
Spacemacs layer configuration more subtle which is not good. There was
additional bad consequences of the removal of Evil state like the
impossibility to use Evil lisp state or iedit states, or we would have
been forced to implement a temporary activation of Evil which is
awkward.
Instead I reintroduce Evil as the central piece of Spacemacs design thus
Evil is now re-enabled in holy-mode. It provides the abstraction we need
to isolate editing styles and be able to grow the Spacemacs
configuration coverage sanely. Layers don't need to check whether the
holy mode is active or not and they don't need to know if Evil is
available (it is always available). We also don't need to write
additional dispatching functions, this is the job of Evil, and I think
it provides everything for this. Ideally configuration layer should be
implemented with only Evil in mind and the holy-mode (and hybrid-mode)
should magically make it work for Emacs style users, for instance we can
freely use `evil-insert-state` anywhere in the code without any guard.
Evil is now even more part of Spacemacs, we can really say that
Spacemacs is Emacs+Evil which is now an indivisible pair. Spacemacs
needed this stable API to continue on the right track.
While these changes should be rather transparent to the user, I'm sorry
for this experimental period, I failed to see all the implications of
such a change, I was just excited about the possibility to make Evil
optional. The reality is that Spacemacs has to embrace it and keep its
strong position on being Emacs+Evil at the core.
Implementation
- insert, motion and normal states are forced to emacs state using an
advice on `evil-insert-state`, `evil-motion-state` and
`evil-normal-state` respectively. These functions can be used freely in
the layer configuration.
- A new general hook `spacemacs-editing-style-hook` allow to hook any
code that need to be configured based on the editing style. Functions
hooked to this hook takes the current style as parameter, this
basically generalize the hook used to setup hjkl navigation bindings.
- ESC has been removed from the emacs state map.
- Revert unneeded changes
- Revert "evil: enter insert-state only from normal-state"
commit bdd702dfbe.
- Revert "avoid being evil in deft with emacs editing style"
commit f3a16f49ed.
Additional changes
All editing style packages have been moved to a layer called
`spacemacs-editing-styles`
Notes
I did not have time to attack hybrid mode, I should be able to do it
later.
evil-set-initial-state is safer than manually adding and deleting from
the lists, because it knows about all available states and ensures that
the mode only shows up in one list. If it is in multiple list the
initial state depends on which is checked first, which we don't want.
This pre-command-hook translates the special key to the corresponding
emacs function key. This effects only happens in terminal, this hook is
a no-op in GUI.
By doing this we attempt to bring more consistency between the GUI
and the terminal regarding TAB and RET keys.
